\\[-1.8ex] Soil Heterogeneity & $-$0.668$^{**}$ & $-$0.461$^{*}$ & $-$0.585$^{**}$ & $-$0.470$^{*}$ & $-$0.328 & $-$0.249 \\ 
  & (0.319) & (0.245) & (0.240) & (0.252) & (0.200) & (0.199) \\ 
\\[-1.8ex] 
Observations & 3,055 & 3,055 & 3,055 & 3,055 & 3,055 & 3,046 \\ 
R$^{2}$ & 0.006 & 0.217 & 0.247 & 0.263 & 0.326 & 0.338 \\ 
